2013 Posts

School starts, and I'm busy again. I have all sorts of cool things to write about, and not enough time to do so. But I'm on top of homework, so here's the conclusion to the combination lock saga!

I wish I could describe the measurements better, but that's a job for engineering drawings, not text. I'll see about making some proper drawings soon.

After deciding on about half the dimensions, we started cutting. The tumblers and washers were first, then I popped a few dowels onto the lathe to turn them down a bit. When I finished, the tumblers spun smoothly on the central shaft.

We assembled the core of the lock with brass screws. First, we slid a washer onto the central shaft, then a tumbler, another washer, and so on until it was built up. After a quick test to make sure everything interfaced well, we screwed the washers into the central dowel with brass screws, being careful to keep the tumblers under a bit of pressure (to prevent wobble and slippage).

Wow. It's been a while since I worked on this. In fact, the whole thing's a bit dusty. I'll give it a good cleaning before I start printing.

Towards the end of last summer, I realized that the old hobbed bolt - the thing that drives filament into the hot end - had worn out. Hobbing is threading on the bolt that grabs the filament and drives it into the hot end. The printer doesn't print so well when it can't push filament.

Recently, I bought another hobbed bolt, and it just arrived!

When I went to swap it in, I found the hobbing (notches) were in the wrong place, and ran to the engineering building for some spacers.

Next problem: with the spacers in place, the gearbox doesn't line up anymore. The big gear stands off too far from the drive gear. So, I popped off the stepper motor and pried at the gear with a screwdriver. (Fun fact: the right tools make anything easier. I don't have the right tools.)

Now to power it up! Steppers - check. USB - check. Power - check. Power supply online. Serial connection up. Temperature probes working. And the Z axis takes a dive.

Not working yet, but it's still alive. Cool.

The X axis is fine, as is Y. Z needed to be plugged back in; one of the connectors had worked loose. And with that, the printer was back. Time to figure out the hot end!

I took apart the hot end, which had fallen apart in transit from home to school, then reassembled it. I also put stronger springs into the cold end - should provide more driving force.

Problem, though. The pocket holes for nuts in the cold end are smaller than the nuts themselves. I guess the saying's true: when all you have is a dremel, everything looks like it needs a good grinding.

So, I ground the holes bigger. What can I say - it worked!

The hot end, cold end, and axes are all together. Time for some testing. And then, god willing, extrusion!

Last year, before I left for college, my parents bought me a Lenovo SL510. I love the computer - it's passably rugged, ugly as sin, its bezel makes a great drawing surface, and it runs Linux like a champ. (I used to dual-boot, but that's neither here nor there.)

In the back right corner, the laptop has a plug for the power adapter. Over the summer, the power plug broke. The adapter connects to the board with some wire; that remained intact. But the plug broke loose from the computer's chassis and started wandering around inside. Most of the time, it'd move a few millimeters, and I'd drag it back to the proper slot, then plug in the power. Last week, it did something different.

Recently, I made a combination lock out of wood. I'll be describing it in a series of articles because to save you, dear reader, from a numbing fifteen hundred word epic.

So, what in the world would posses me to make a combination lock out of wood? Well, some time ago, I saw a working model of a combination lock on woodgears.ca, looked it over, thought it was cool, and stashed the idea in the back of my mind with fulgurates and sous vide.

Months later, I was looking for winter break projects, and I thought of this lock. Helen & I decided to build a pair of them, scaled down from the version that Matthias built on woodgears. Why?